1. Field of the Invention
The present invention relates to the routing of calls in complex telecommunications networks, and more particularly to the routing of calls requiring adjunct-based applications.
2. Description of the Related Art
With the development of complex telecommunications networks, such as AT&T's Switched Network, there continues to be a growing demand for customized call treatment that provides customers with a variety of services through the telecommunications network on calls to general destination numbers. These services may include, but are not limited to, customized billing, call forwarding, answering services, voice messaging, etc.
Since the computer processing switches that route calls within the telecommunications network typically lack sufficient capability to process these customized services, separate processors, referred to as adjuncts and well known in the art, have been incorporated into the network to assist in providing switch service features and capabilities. Accordingly, the service logic and customer records necessary for processing these customized features reside primarily in the adjuncts interfacing with the network.
To access these customized services, a caller would typically be required to specify that an adjunct was required for a particular call by dialing a specific telephone number, i.e., a 1-800-xxx-xxxx telephone number, in order to access the adjunct for that particular customized service. Once connected to the adjunct, the caller would then be required to dial the destination or termination telephone number, which is the telephone number that the caller ultimately wishes to be connected to.
In the prior art method of accessing an adjunct as illustrated in FIG. 1, the customer identified the need for and type of adjunct required by dialing a specific telephone number that is not the destination number ultimately desired by that customer. The call would be routed from an originating or access switch (OSW) in the network (and possibly through other switches) to the adjunct that processes the particular customer service application sought by the caller. Once connected to the adjunct, the caller then typically dials the destination number and the call is routed through the adjunct and possibly other switches to the terminating or destination switch (DSW) to complete the call to the particular destination number.
This prior art method of accessing the customized service is prohibitive, costly and inefficient for several reasons. For instance, the responsibility for identifying the need to access an adjunct to process a particular customer service is borne by the customer rather than the network itself.
The adjunct in the prior art system was also required to stay on-line during the entire connect time of the call to the destination number, regardless of whether the adjunct had completed the processing of the customer service application and was no longer necessary.
Additionally, since the adjunct remains on-line during the entire call, the communication paths or trunks to and from the adjunct and switches also remain unavailable during the entire length of the call, thereby tying up valuable network resources.
Finally, in the event that the adjunct associated with the particular application or the network path fails or is otherwise unavailable, the call is terminated because there exists no backup or alternate routing capability in the prior art method.